Laura J. NelsonThis post has been updated. See notes below for details.

City transportation employees are expected to speak out at Wednesday's Los Angeles City Council meeting about policies they say are putting commuters at risk -- the second time in a month they have criticized how their workplace is run.

At least 100 high-ranking supervisors, maintenance crews and traffic officers are expected at the meeting, union representatives said. Some will address complaints about how the department is managed, including recent reshuffling of senior employees and contracts for city work awarded to private companies. The staff members say such changes have made it harder to regulate commuting and traffic issues.

At the end of September, more than 100 transportation employees walked into Mayor Eric Garcetti's office and aired similar grievances to one of his senior staff members, according to an email obtained by The Times.

[Updated at 9:04 a.m., Oct. 16: De La Vega said the department views the reassignment of senior engineering managers as "essential to professional development." The approach had been explained to engineers and union leadership, he said, and was consistent with a management review that then-Controller Wendy Greuel conducted three years ago.

"Given budgetary constraints and attrition, not every position—senior engineer or otherwise—is filled at all times," De La Vega wrote in an email. "This has been explained to the union leadership."]

In the email sent in late September, transportation engineer Michael Hunt wrote that De La Vega had "promoted policies that have hurt LADOT," including not filling key vacant positions and transferring senior engineers away from their areas of expertise. He said it had doubled the staff's workload.

The email also said the department held contracts with 40 private companies, which some staff members call the "bench list." Union representatives declined to specify which contracts are at issue Tuesday, but said outside firms sometimes charge three to four times what the city would pay to perform the work in-house.

[Updated at 9:04 a.m., Oct. 16: De la Vega said although the city holds contracts with engineering, consulting and professional services firms, no work had been assigned yet.

"A professional bench is a wise move, and not unprecedented," De La Vega wrote. He said they would be used for work that the department doesn't have the manpower or skill set to complete. The department would prefer to keep work in-house, de la Vega said, and has not yet assigned any work to those companies.]

"These changes have been frustrating," Hunt wrote in the email, which was sent to employees affiliated with SEIU Local 721. "We've been clear with LADOT management about these errors and offered solutions to fix them -- but we've been ignored."

The email went on to say that mayoral staff promised Garcetti would hear their concerns. Hunt concluded: "If we need to take action again, we will."